Now that most callers use mobile devices, locating an emergency caller has become a critical component of the emergency response process. Known technologies used to identify a caller's location can include but are not limited to trilateralization and/or triangulation off of cell tower signals or other RF signals, IP-access point identification, near-field communications (NFC), and GPS.
In today's network, the location used to initially route a mobile call is often based off the cell tower sector with which the device is communicating. The local network has a mobile positioning center that can then request an update for a more accurate location. This requesting process is known in the industry as “rebidding.”
The location information is provided through an automatic location identification (ALI) database and made available to the Public Safety Access Point (PSAP) on its local equipment. The rebid location provides the call taker/dispatcher at the PSAP with a more accurate, and optimally “dispatch-quality” location than what is available through the coarse cell-tower or cell-sector determined location used for initial call routing. As used herein, a “dispatch-quality” location is a location that is accurate enough to direct a first responder directly to the location of the device used to place the 9-1-1 call.
Existing location technologies rely on the network to identify the dispatchable location of the caller, either through the trilaterilizaton or triangulation techniques, or GPS. It is also done by request.
In contrast many commercial location technologies reside on the handset itself. Such systems use the device's own computational power to calculate its location based on whatever technologies are available. Increasingly, devices are able to use a broad spectrum of RF signals, GPS and even embedded barometric pressure devices to calculate the device's latitude, longitude, and altitude or floor. Devices can do all this more accurately than network-based technologies. In many cases the device's location accuracy also improves over time as the device is able to recognize more signals and clear any internal caches on the device itself that may exist from previous attempts to fix location.
There are several challenges to utilizing handset-based technologies for 9-1-1 and emergency calling purposes.
First, in an emergency, call connect time is critical. Many technologies take ten to thirty seconds to calculate a granular location. This is no problem for mere navigation. But is a significant issue for an emergency.
Second, the current network is not designed to have the device push a location directly into the network. The network itself routes the call based on the cell tower and sometimes the cell sector serving the call. It then forwards the call to the PSAP that has been pre-determined to serve the identified caller area. Although this allows for rapid routing of the 9-1-1 call to the PSAP, it does not lend itself to providing “dispatch-quality” location data.
The location data used for routing is made available through the ALI database, which can be queried by PSAP systems. As time progresses, subsequent rebids of the caller's location may produce more accurate location data for the caller. However, the current E911 architecture is unable to provide dispatch-quality location on enough calls to satisfy either the public or public safety practitioners (see FCC Wireless E911 Location Accuracy Requirements, Fourth Report and Order, Released Feb. 3, 2015). E911 networks are not designed to carry location data. They are primarily designed for calls. Finally, the existing systems rely on the PSAP requesting location updates through a “re-bid” process; the emergency operator is not proactively notified of location updates (e.g. to identify when more accurate location data is available, and/or the caller has moved).
Additionally, it is becoming prevalent for a 9-1-1 “call” to include or to consist of only a communication using some other medium, including text messaging, instant messaging, videos, email, etc. In the United States, the public safety industry has undertaken a massive effort, termed NG911, to design and enable an infrastructure to support these new forms of communication at the over six thousand PSAPs that answer 9-1-1 calls.